In recent years, three-dimensional computer graphic (hereinafter, abbreviated as 3D CG) are widely used in computers and programming broadcasts, and when characters or the like which are originally two-dimensional (2D) symbols are also used in a 3D virtual space, these characters can be made consistent with other objects that constitute the virtual space, or they can be variously decorated. Accordingly, there are more and more cases where these 2D characters or the like are handled as solid 3D graphics. In order to represent 2D graphics like characters in the 3D CG, 3D graphics should be generated from the 2D graphics. As an example of conventional 3D graphic generation apparatus, there is a 3D character creation apparatus that is disclosed in Japanese Published Patent Application No. Hei.63-103380.
Hereinafter, the conventional 3D character creation apparatus will be described with reference to FIG. 17. FIG. 17 is a block diagram showing functions of the conventional 3D character creation apparatus.
When a 3D character is created by this conventional 3D character creation apparatus, a 2D character is first inputted through a 2D character input unit 640. By this input, the 2D character on a x-y plane is stored in a storage unit 620. Next, the 2D character stored in the storage unit 620 is displayed on a display unit 601, and then the shape of a 3D character is designed by operating a z-direction retouch unit 630 while seeing the image on the display unit 610. More specifically, the z coordinate of each point is changed on the x-z projection plane 612 or y-z projection plane 613 of the display unit 610 by the z-direction retouch unit 630. Then, the 3D character that has been generated by the above-mentioned retouch is stored in the storage unit 620. Here, the solid object image of the 3D character that is being retouched can be checked on a solid object projecting plane 614. Further, when image data of a design is inputted from a design and background input unit 650, image data of the 3D character in the storage unit 620 having the design attached thereto is generated, and then this image is displayed on the solid object projecting plane 614.
However, to create 3D characters by the above-mentioned conventional 3D character creation apparatus, inputted 2D characters should be retouched and transformed into 3D characters manually by operators. Therefore, when the 3D characters are created by employing the prior art apparatus, the operators are heavily burdened. Further, in order to create finely decorated 3D characters by employing the above-mentioned apparatus, the operator is required to be expert in the retouch process, and thus 3D characters of high quality cannot be easily created.